The term “biodiesel” refers to methyl or ethyl esters that are generally between 8 and 25 carbons in length. Biodiesel typically is derived from tri-glyceride oils. Current sources of tri-glyceride oils for the production of biodiesel include plants (e.g., soybean, canola, corn, and sunflower), recycled cooking oil, and animal fat. Tri-glyceride oils can be converted into biodiesel by transesterification, which is a reaction to replace glycerol groups with alcohol groups. Catalysts useful for this reaction include sodium hydroxide and potassium hydroxide. Useful alcohol reactants include methanol and ethanol.
A variety of potential uses for biodiesel exist in addition to its most prominent use as fuel oil. The uses include various cleaning and solvent uses, such as hand cleaning, petroleum degreasing, paint removal, lubrication of metal cutting tools, adhesive removal, and rust prevention. In addition, U.S. Pat. No. 6,764,542 discloses the use of biodiesel as an additive for reducing the viscosity of asphalt. Similarly, U.S. Pat. No. 6,827,841 discloses the addition of biodiesel to petroleum pitch. Despite these disclosures, the widespread use of biodiesel for applications other than fuel applications has been limited.